/**
 * @author LKQ
 * @date 2021/12/30 10:27
 * @description 快慢指针
 */
public class Solution1 {
    public static void main(String[] args) {

    }
    public ListNode middleNode(ListNode head) {
        ListNode slow = head, fast = head;
        while (fast != null && fast.next != null) {
            slow = slow.next;
            fast = fast.next.next;
        }
        return slow;
    }
}
